Tumors of parenchymatous organs or tumors penetrating hollow internal organs are known to be treatable by hyperthermia induced by radiofrequency. Such a treatment is made with suitable radiofrequency generators provided with a passive electrode to be applied outside the patient's body and with an active electrode to be inserted into the patient's body and directly contacting the tumor. The known active electrodes consist of variously sized needles which are inserted into the patient's body by passing them through several layers of the body tissue. This results in drawbacks due to the passing through tissues other than the one to be treated, some of which are not pierceable by large-sized catheters.
From WO 9428809 a transurethral device is already known, which does not require the piercing of tissues other than the one to be treated, but it is limited to the treatment of prostatic hyperplasia and it is not provided with means allowing a real-time monitoring of the temperature of the treated tissue.
WO 96134570 discloses a system for ablating body tissue by hyperthermia using an active electrode which has the shape of a bulb in order to focus the heat on the terminal cap of the bulb-shaped electrode. While this shape of the electrode is appropriate for the treatment of heater tissues, it is no appropriate for the treatment of prostatic hyperplasia where large surfaces of body tissue are to be ablated.
EP 0 629 382 A1 discloses a catheter assembly for the treatment of prostatic hyperplasia wherein the active electrode has the shape of a needle to be driven into the tissue with the drawbacks of the above-mentioned known devices using needles as active electrodes.
The object of the present invention is therefore to provide a device, suitable for the use in thermal ablation of tumors, which is free from the above mentioned drawbacks. Such an object is achieved by the device having the features specified by claim 1, which may be brought in contact or close to the tumor by passing it through natural ways being patent or made patent.
The device according to the present invention has the advantage of being usable in the treatment by hyperthermia of tumors lying in close contact with hollow internal organs, or passed through by hollow internal organs, as well as of tumors penetrating hollow internal organs. For example, the device according, to the present invention may be advantageously used in the treatment of prostatic tumors by passing it through the urethra, of uterus tumors by passing it through the uterine canal, of colangiocarcinoma by passing it through the bile ducts and of pancreas tumors by passing it through the main pancreatic duct.
Another advantage of the device according to the present invention is the fact that it allows to focalize the energy even in very small-sized tissue areas to be treated, whereas in the known devices the needle-shaped active electrodes operate on 360.degree..